Converting to and from Python lists in NumPy - Mini Project: Build & Apply

Converting to and from Python lists

📖 Scenario: Imagine you work in a small bakery. You have a list of daily sales numbers. You want to use NumPy to do some quick calculations, but first, you need to convert your Python list into a NumPy array. Later, you want to convert the NumPy array back to a Python list to share with your team.

🎯 Goal: Learn how to convert a Python list to a NumPy array and then convert it back to a Python list.

📋 What You'll Learn

Create a Python list with exact sales numbers

Import the NumPy library

Convert the Python list to a NumPy array

Convert the NumPy array back to a Python list

Print the final Python list

💡 Why This Matters

🌍 Real World

Data scientists often receive data in Python lists but use NumPy arrays for fast calculations. Knowing how to switch between these formats helps in data cleaning and sharing results.

💼 Career

This skill is essential for data analysts and scientists who work with numerical data and need to prepare it for analysis or visualization.

1

Create the sales list

Create a Python list called sales with these exact numbers: 15, 22, 13, 27, 19.

NumPy

# Create the sales list with the exact numbers
# Your code here

Need a hint?

Use square brackets [] to create a list and separate numbers with commas.

2

Import NumPy and convert list to array

Import the NumPy library as np. Then create a NumPy array called sales_array by converting the sales list using np.array().

NumPy

sales = [15, 22, 13, 27, 19]
# Import numpy as np and convert sales to sales_array
# Your code here

Need a hint?

Use import numpy as np to import NumPy. Use np.array() to convert the list.

3

Convert NumPy array back to Python list

Create a new variable called sales_list_again by converting the sales_array NumPy array back to a Python list using the tolist() method.

NumPy

import numpy as np

sales = [15, 22, 13, 27, 19]
sales_array = np.array(sales)
# Convert sales_array back to a Python list called sales_list_again
# Your code here

Need a hint?

Use the tolist() method on the NumPy array to get a Python list.

4

Print the final Python list

Print the variable sales_list_again to display the Python list converted back from the NumPy array.

NumPy

import numpy as np

sales = [15, 22, 13, 27, 19]
sales_array = np.array(sales)
sales_list_again = sales_array.tolist()
# Print sales_list_again
# Your code here

Need a hint?

Use print() to show the list on the screen.